Generally, a patient can be scanned and imaged by a variety of imaging techniques in order to make diagnosis. Such imaging techniques can include X-ray imaging, magnetic resonance imaging (MRI), computer tomography (CT), positron emission tomography (PET) and the like. A patient imaging and carrying apparatus employing such imaging techniques generally includes a movable table so as to carry and position the patient accurately.
As shown in FIG. 1, a patient imaging and carrying apparatus includes the following three portions: a table 21, an imaging system 22 and a rear pedestal 23. In this apparatus, the imaging system 22 is an X-ray imaging system. The table 21 is movable, in order to get close to the imaging system 22. The table 21 can also move up and down so that the vertical position of the patient can be adjusted. The table 21 includes a cradle 24, and the cradle 24 can move relative to the table 21 in order to carry the patient into the space of the imaging system 22. When the front part of the cradle 24 passes through the imaging system 22 and moves out of the imaging system 22, a bridge 25 within the imaging system 22 can support the cradle 24. The rear pedestal 23 includes a cradle traction element 26 and a drive motor 27 thereon. The drive motor 27 can drive the cradle traction element 26. The cradle traction element 26 can pass through and protrude out of the imaging system 22 to couple with the cradle 24, thereby to drive the cradle 24 to move.
The structure of such apparatus has the following problems. Firstly, the existence of the rear pedestal 23 causes a complex structure and requires a rather larger room, such that this apparatus has high cost and the physician is not convenient to operate on the patient while performing imaging for diagnosis due to the rear pedestal 23. Secondly, because the cradle 24 needs to be supported by the bridge 25 and the bridge 25 may attenuate a portion of the X-ray, a dose of the X-ray emitted should be increased to assure a normal imaging. However, this increased dose of the X-ray is detrimental to the patient.
Further, the above cradle 24 generally slides relative to the table 21. For example, referring to FIG. 2, a cradle utilizing the sliding movement is shown, and which is described in U.S. Pat. No. 6,782,571. The cradle 820 shown in FIG. 2 can be used in the X-ray imaging system, and is an elongated member with a wide end 822, a middle 824 and a narrow end 826. The cradle 820 includes rails 840 which are configured to be received by guide rails. The rails 840 are only located at the wide end 822 of the cradle 820, such that the cradle 820 is a cantilever structure.
However, this sliding structure also has the following problems. Firstly, the cantilever structure is complex, and can increase the cost of the whole imaging system. Secondly, the cradle 820 with the cantilever structure tends to sag at a location lacking support when the patient is carried on the cradle 820. A large deformation of the cradle 820 will cause inaccurate locating for the part of the patient to be imaged.
Therefore, there is a need for a cradle drive mechanism, a table and a patient imaging and carrying apparatus that can overcome the above mentioned disadvantages.